SO advice

So, my fiancé and I are trying to get pregnant. I have PCOS and he knows there's a slim chance of it happening (we're looking into adoption as well) but last night he dropped the bomb on me that since he was the only boy in his family he feels the need to have a biological baby to carry on the name. When we first got together and started talking about the future possibility of kids I let him know adoption would be the best option for us as I've never had a regular period without birth control pills and he said that he had always wanted to adopt and was thrilled at the idea. Now, fast forward a year, he suddenly feels the need to have a biological baby and told me he would be extremely upset if we couldn't.